Dados do Trabalho

Título

Structural changes in pumpkin seed protein hydrolysates obtained by ultrasound-assisted proteolysis

Introdução

In recent years, studies have focused on obtaining protein hydrolysates from plant residues to add commercial value and reduce waste. Pumpkin seed (Cucurbita pepo) is a promising source of protein and protein hydrolysis allows the production of ingredients with high applicability in the food and pharmaceutical industries. However, the industrial enzymatic hydrolysis presents some challenges, due to the high cost of the enzymes, long reaction time, low degree of hydrolysis and limited yield. To overcome these obstacles, ultrasound (US) has been used to improve enzyme performance. However, the impact on the macrostructural characteristics of these hydrolysates is scarce. Thus, this work investigated the impact of US-assisted hydrolysis by three commercial proteases (Brauzyn®, Flavourzyme® and Neutrase®) on the conformational characteristics of pumpkin seed protein (PSP) hydrolysates.

Material e Métodos

Enzymatic hydrolysis was carried out in a bath US (40kHz, 23.8W/L) at pH 7.5 for 180 min at optimum temperature for each enzyme (60 °C for Brauzyn®, 55 °C for Flavourzyme® and 50 °C for Neutrase®). Conventional hydrolysis was performed using the same conditions in a thermostatic bath. After hydrolysis, the hydrolysates were subjected to zeta potential (ζ), mean particle size (MPS), polydispersity index, intrinsic fluorescence and UV spectroscopy analyses.

Resultados e Discussão

The results revealed an increase in fluorescence intensity (up to 68% - Brauzyn® reaction) and in the UV absorbance spectra (up to 211% at 280nm - Flavourzyme® reaction) for the samples hydrolyzed under US compared to hydrolysates obtained in conventional reaction. Likely, these results stem from the increased generation of smaller-sized hydrolysates obtained in US-assisted reactions (reduction in MPS of up to 67% - Flavourzyme® reaction), resulting in lower PDI values (up to 31%), which contributed to greater homogeneity and dispersion of the hydrolysates in suspension (increase in ζ of up to 100% - Neutrase® reaction).

Conclusão

Therefore, these results suggest that US-assisted hydrolysis was capable of promoting structural modifications in pumpkin seed protein hydrolysates, which could broaden their utilization as protein ingredients with enhanced stability and techno-functional properties.